Identification of regions on the fusion protein of human parainfluenza virus type 2 which are required for haemagglutinin-neuraminidase proteins to promote cell fusion.
Using a plasmid expression system in HeLa cells, we have previously shown that the fusion (F) protein of simian virus 41 (SV-41) induces cell fusion when coexpressed with the haemagglutinin-neuraminidase (HN) protein of human parainfluenza virus type 2 (PIV-2), while the PIV-2 F protein does not induce cell fusion with the SV-41 HN protein. In the present study, we found that the PIV-2 F protein induced extensive cell fusion with the HN protein of mumps virus (MuV), whereas the SV-41 F protein did not. Chimaeric analyses of the F proteins of PIV-2 and SV-41 identified two regions (designated M1 and M2) on the PIV-2 F protein, either of which was necessary for chimaeric F proteins to show fusogenic activity with the MuV HN protein. Subsequently, two additional regions (P1 and P2) were identified on the PIV-2 F protein, both of which were necessary for chimaeric F proteins to prevent induction of cell fusion with the SV-41 HN protein. Consequently, it was proved that a given chimaeric F protein, harbouring regions P1 and P2 together with either of region M1 or M2, induced cell fusion specifically with HN proteins of PIV-2 and MuV, the same as the PIV-2 F protein. Region M2 was located at the membrane proximal end of the PIV-2 F1 ectodomain, while regions P1, M1 and P2 clustered together in the middle of the ectodomain. These regions on the PIV-2 F protein may be involved in a putative functional interaction with HN proteins, which is considered to be a prerequisite for cell fusion.
Tsurudome
M
M
Department of Microbiology, Mie University School of Medicine, Tsu, Japan. turudome@doc.medic.mie-u.ac.jp
Ito
M
M
Nishio
M
M
Kawano
M
M
Okamoto
K
K
Kusagawa
S
S
Komada
H
H
Ito
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D002459:Cell Fusion; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology; D002522:Chlorocebus aethiops; D015707:HN Protein / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010223:Parainfluenza Virus 2, Human / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry; D019213:Rubulavirus / Q000502:physiology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014760:Viral Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000502:physiology*
D015707:HN Protein; D011993:Recombinant Fusion Proteins; D014760:Viral Fusion Proteins